Scientists have gotten around to taking a good look at the sticky mystery of how spiders are able to cling to any surface. Taking ultra-close up shots using a scanning electron microscope the secret becomes clear: The crafty arachnids are using physics to do their wall walking stunts. Specifically, their “feet” are designed to make use of the van der Waals force.
Andrew Martin, from the Institute of Technical Zoology and Bionics in Germany, said, “We found out that when all 600,000 tips are in contact with an underlying surface the spider can produce an adhesive force of 170 times its own weight. That’s like Spiderman clinging to the flat surface of a window on a building by his fingertips and toes only, whilst rescuing 170 adults who are hanging on to his back!”
What makes the van der Waals force an interesting form of adhesion is that, unlike many glues, the surrounding environment does not affect it. The only thing that affects it is the distance between the two objects.
“One possible application of our research would be to develop Post-it notes based on the van der Waals force, which would stick even if they got wet or greasy,” said Professor Antonia Kesel, head of the research group in Bremen. “You could also imagine astronauts using spacesuits that help them stick to the walls of a spacecraft—just like a spider on the ceiling.”
The total van der Waals force on the spider’s feet is very strong, but it is the sum of many very small forces on each molecule. The researchers believe the spider lifts its leg so that the setules are lifted successively, not all at once, and it does not need to be very strong to do this. All you would have to do to lift a future kind of Post-itή note is peel it off slowly.
So they’re using a natural phenomena at a molecular level to cling to surfaces. Pretty cool, though the pic of the foot is enough to give you nightmares.
Link found via BoingBoing.